Cleanup

Author: BrianRothermich

server/src/main/java/org/elasticsearch/index/engine/ThreadPoolMergeScheduler.java

@@ -30,9 +30,7 @@
 import org.elasticsearch.index.merge.OnGoingMerge;
 import org.elasticsearch.index.shard.ShardId;
 
-import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.nio.file.NoSuchFileException;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.Locale;
@@ -541,17 +539,14 @@ public OnGoingMerge getOnGoingMerge() {
         private static long getNewSegmentSize(MergePolicy.OneMerge currentMerge) {
             try {
                 return currentMerge.getMergeInfo() != null ? currentMerge.getMergeInfo().sizeInBytes() : currentMerge.estimatedMergeBytes;
-            } catch (FileNotFoundException | NoSuchFileException e) {
-                // It is (rarely) possible that the merged segment could be merged away by the IndexWriter prior to reaching this point.
-                // Once the IW creates the new segment, it could be exposed to be included in a new merge. That merge can be executed
-                // concurrently if more than 1 merge threads are configured. That new merge allows this IW to delete segment created by
-                // this merge. Although the files may still be available in the object store for executing searches, the IndexDirectory
-                // will no longer have references to the underlying segment files and will throw file not found if we try to read them.
-                // In this case, we will ignore that exception (which would otherwise fail the shard) and use the originally estimated
-                // merge size for metrics.
-                return currentMerge.estimatedMergeBytes;
             } catch (IOException e) {
-                // TODO how to handle?
+                // For stateless only: It is (rarely) possible that the merged segment could be merged away by the IndexWriter prior to
+                // reaching this point. Once the IW creates the new segment, it could be exposed to be included in a new merge. That
+                // merge can be executed concurrently if more than 1 merge threads are configured. That new merge allows this IW to
+                // delete segment created by this merge. Although the files may still be available in the object store for executing
+                // searches, the IndexDirectory will no longer have references to the underlying segment files and will throw file not
+                // found if we try to read them. In this case, we will ignore that exception (which would otherwise fail the shard) and
+                // use the originally estimated merge size for metrics.
                 return currentMerge.estimatedMergeBytes;
             }
         }

server/src/test/java/org/elasticsearch/index/engine/ThreadPoolMergeSchedulerTests.java

@@ -516,7 +516,7 @@ public void testSchedulerCloseWaitsForRunningMerge() throws Exception {
                     IndexSettingsModule.newIndexSettings("index", settings),
                     threadPoolMergeExecutorService,
                     merge -> 0,
-                    mock(MergeMetrics.class)
+                    MergeMetrics.NOOP
                 )
             ) {
                 CountDownLatch mergeDoneLatch = new CountDownLatch(1);
@@ -580,7 +580,6 @@ public void testAutoIOThrottleForMergeTasksWhenSchedulerDisablesIt() throws Exce
         ThreadPoolMergeExecutorService threadPoolMergeExecutorService = mock(ThreadPoolMergeExecutorService.class);
         MergePolicy.OneMergeProgress oneMergeProgress = new MergePolicy.OneMergeProgress();
         OneMerge oneMerge = mock(OneMerge.class);
-        MergeMetrics mergeMetrics = mock(MergeMetrics.class);
         when(oneMerge.getStoreMergeInfo()).thenReturn(getNewMergeInfo(randomNonNegativeLong()));
         when(oneMerge.getMergeProgress()).thenReturn(oneMergeProgress);
         MergeSource mergeSource = mock(MergeSource.class);
@@ -591,7 +590,7 @@ public void testAutoIOThrottleForMergeTasksWhenSchedulerDisablesIt() throws Exce
                 indexSettings,
                 threadPoolMergeExecutorService,
                 merge -> 0,
-                mergeMetrics
+                MergeMetrics.NOOP
             )
         ) {
             threadPoolMergeScheduler.merge(mergeSource, randomFrom(MergeTrigger.values()));
@@ -610,7 +609,6 @@ public void testAutoIOThrottleForMergeTasks() throws Exception {
         IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("index", settingsBuilder.build());
         MergePolicy.OneMergeProgress oneMergeProgress = new MergePolicy.OneMergeProgress();
         OneMerge oneMerge = mock(OneMerge.class);
-        MergeMetrics mergeMetrics = mock(MergeMetrics.class);
         // forced merge with a set number of segments
         when(oneMerge.getStoreMergeInfo()).thenReturn(getNewMergeInfo(randomNonNegativeLong(), randomNonNegativeInt()));
         when(oneMerge.getMergeProgress()).thenReturn(oneMergeProgress);
@@ -623,7 +621,7 @@ public void testAutoIOThrottleForMergeTasks() throws Exception {
                 indexSettings,
                 threadPoolMergeExecutorService,
                 merge -> 0,
-                mergeMetrics
+                MergeMetrics.NOOP
             )
         ) {
             threadPoolMergeScheduler.merge(mergeSource, randomFrom(MergeTrigger.values()));
@@ -641,7 +639,7 @@ public void testAutoIOThrottleForMergeTasks() throws Exception {
                 indexSettings,
                 threadPoolMergeExecutorService,
                 merge -> 0,
-                mergeMetrics
+                MergeMetrics.NOOP
             )
         ) {
             // merge submitted upon closing
@@ -659,7 +657,7 @@ public void testAutoIOThrottleForMergeTasks() throws Exception {
                 indexSettings,
                 threadPoolMergeExecutorService,
                 merge -> 0,
-                mergeMetrics
+                MergeMetrics.NOOP
             )
         ) {
             // merge submitted upon closing
@@ -676,14 +674,13 @@ public void testAutoIOThrottleForMergeTasks() throws Exception {
 
     public void testMergeSchedulerAbortsMergeWhenShouldSkipMergeIsTrue() {
         ThreadPoolMergeExecutorService threadPoolMergeExecutorService = mock(ThreadPoolMergeExecutorService.class);
-        MergeMetrics mergeMetrics = mock(MergeMetrics.class);
         // build a scheduler that always returns true for shouldSkipMerge
         ThreadPoolMergeScheduler threadPoolMergeScheduler = new ThreadPoolMergeScheduler(
             new ShardId("index", "_na_", 1),
             IndexSettingsModule.newIndexSettings("index", Settings.builder().build()),
             threadPoolMergeExecutorService,
             merge -> 0,
-            mergeMetrics
+            MergeMetrics.NOOP
         ) {
             @Override
             protected boolean shouldSkipMerge() {